package com.nxu.util;

import javax.crypto.Cipher;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;
import javax.crypto.spec.IvParameterSpec;
import java.security.Key;
import java.util.Locale;

public class DESCode {

    private static final String key = "povckmb84.'!@#!@a13513asssdsgdda770a";
    private static final String ALGORITHM_DES = "DES/CBC/PKCS5Padding";


    /**
     * 实现DES密码加密
     * @param desMode
     * @return
     */
    private static Cipher getCipher(int desMode) {
        Cipher cipher = null;
        try {
            DESKeySpec dks = new DESKeySpec(key.getBytes());
            SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");
            Key secretKey = keyFactory.generateSecret(dks);
            cipher = Cipher.getInstance(ALGORITHM_DES);
            IvParameterSpec iv = new IvParameterSpec("12345678".getBytes());
            cipher.init(desMode, secretKey, iv);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return cipher;
    }

    public static String encode(String data) {
        if (data == null || "".equals(data.trim())) return null;
        try {
            byte[] bytes = getCipher(Cipher.ENCRYPT_MODE).doFinal(data.getBytes());
            return byte2String(bytes);
        } catch (Exception e) {
            e.printStackTrace();
            return data;
        }
    }

    public static void main(String[] args) {
        System.out.println(encode("m131163"));
    }

    public static String decode(String data) {
        if (data == null || "".equals(data.trim())) return null;
        try {
            return new String(getCipher(Cipher.DECRYPT_MODE).doFinal(byte2hex(data.getBytes())));
        } catch (Exception e) {
            e.printStackTrace();
            return data;
        }
    }

    private static String byte2String(byte[] b) {
        StringBuilder hs = new StringBuilder();
        String str;
        for (int n = 0; b != null && n < b.length; n++) {
            str = Integer.toHexString(b[n] & 0XFF);
            if (str.length() == 1) {
                hs.append('0');
            }
            hs.append(str);
        }
        return hs.toString().toUpperCase(Locale.CHINA);

    }

    private static byte[] byte2hex(byte[] b) {
        if ((b.length % 2) != 0) {
            throw new IllegalArgumentException();
        }
        byte[] b2 = new byte[b.length / 2];
        for (int n = 0; n < b.length; n += 2) {
            String item = new String(b, n, 2);
            b2[n / 2] = (byte) Integer.parseInt(item, 16);
        }
        return b2;
    }
}
